After months of protests, the death of 1,300 people and the displacement of hundreds of thousands more this year, Kenya's post-election crisis was settled in a way that might have seemed obvious from the start: power-sharing.

The agreement brokered by Kofi Annan after weeks of negotiations was ultimately simple. Mwai Kibaki, who had prevailed in a dubious election, kept his job, but saw his authority diluted. Raila Odinga, the opposition leader who insisted Kibaki step down, was given the post of prime minister.

The unity government they formed gave their respective parties equal weight. Ministerial posts were split 50-50, while each minister was shadowed by an assistant minister from the opposite side. So far, the coalition has held up, confounding sceptics.

Key to the deal was that both sides had incentives to compromise. Kibaki's faction knew that without concessions the government would not gain international legitimacy. Odinga realised that the violence being carried out in his name was damaging his reputation. This is the crucial difference with the situation in Zimbabwe, where the government is responsible for the manipulation of the vote and the violence.